Despite ground fog which rolled across Vandenberg Air Force Base, Calif., virtually obscuring the star of the show from view in its final minutes on Earth, SpaceX successfully delivered its 15th and final Falcon 9 v1.1 booster aloft earlier today (Sunday, 17 January) and transported the joint NASA/NOAA Jason-3 ocean altimetry mission into a polar orbit which will carry it from an altitude of 825 miles (1,328 km) at perigee to 857 miles (1,380 km) at apogee. The on-time launch took place on the opening of a 30-second “window” at 10:42:18 a.m. PST (1:42:18 p.m. EST) from Space Launch Complex (SLC)-4E at the West Coast launch facility and served to redeem the v1.1’s reputation one last time, following its catastrophic failure last June. It also appeared that the attempt to land its first-stage hardware on the deck of the Autonomous Spaceport Drone Ship (ASDS) was achieved successfully, though harder than intended, resulting in the breakage of one of the Falcon 9’s quartet of landing legs.
“The 30th Space Wing takes pride in supporting the successful launch of the new ocean monitoring satellite with the NASA and SpaceX teams,” said Col. Shane Clark, Vice Commander of the 30th Space Wing at Vandenberg, who served as Launch Decision Authority. “Today’s launch is a testament to the professionalism and commitment to mission assurance, public safety, and mission success on the Western Range.”
As outlined in a previous AmericaSpace article, today’s mission represented the 15th and final flight of the Falcon 9 v1.1, a two-stage booster with the potential to deliver 28,990 pounds (13,150 kg) into low-Earth orbit and up to 10,690 pounds (4,850 kg) into Geostationary Transfer Orbit (GTO). First flown in September 2013, the v1.1 boasts nine Merlin 1D engines on its first stage—configured with a circle of eight engines and a ninth in the center—which produce 1.3 million pounds (590,000 kg) of propulsive yield at T-0, together with a single Merlin 1D Vacuum engine on its second stage, capable of 180,000 pounds (81,600 kg) of thrust. This was expected to be more than sufficient to deposit the 1,150-pound (525-kg) Jason-3 satellite into its near-circular low-Earth orbit of 825 miles (1,328 km) x 857 miles (1,380 km).
Since its maiden voyage, the v1.1 has transported seven commercial communications satellites into GTO, together with NASA’s Deep Space Climate Observatory (DSCOVR) to the L1 Lagrange Point—representing SpaceX’s first foray beyond Earth orbit—as well as launching five Commercial Resupply Services (CRS) Dragon cargo vessels toward the International Space Station (ISS). All but one of those Dragons successfully reached their destination, with the ill-fated CRS-7, last 28 June, suffering a catastrophic failure late in first-stage flight, leaving the v1.1 with a cumulative 93.3-percent success rate. The v1.1’s achievement comes on the back of its predecessor, the Falcon 9 v1.0, which flew five times, all successfully, between June 2010 and March 2013. Future missions will be executed by the Upgraded Falcon 9, which debuted last month, and the forthcoming Falcon Heavy, which is currently aiming for a maiden flight by mid-2016.
As highlighted by AmericaSpace’s Mike Killian, the Flight Readiness Review (FRR) was conducted on 8 January, followed by a customary Static Fire Test of the nine Merlin 1D first-stage engines on the evening of the 11th. The Falcon 9 was then removed from the SLC-4E pad surface and returned to a horizontal configuration, allowing for the integration of the Jason-3 satellite—by now encapsulated within its bulbous Payload Fairing (PLF)—and final checks. Following completion of the Launch Readiness Review (LRR) on Friday, 15 January, the booster, which stood approximately 224 feet (68.5 meters) tall, was elevated to a vertical orientation at SLC-4E by 11:11 a.m. PST (2:11 p.m. EST) Saturday.
Sunday dawned fine at Vandenberg, with Launch Weather Officer Lt. Joseph Round of the 30th Operations Support Squadron declaring a “rare” 100-percent probability of acceptable meteorological conditions at T-0. Due to the nature of Jason-3’s precise orbit, which will require it to function in tandem with the 2008-launched Jason-2 satellite, this next-generation member of an ocean-monitoring network—which began in 1992 with the joint U.S./French TOPEX/Poseidon and was continued by the 2001-launched Jason-1—was restricted to a 30-second “window,” which opened at 10:42:18 a.m. PST (1:42:18 p.m. EST). NASA reported that launch managers and controllers took their stations early Sunday, before pressing ahead with polling to ensure that all systems were ready to begin fueling the Falcon 9.
Unlike the Upgraded Falcon 9—which utilizes “densified” cryogens, capable of being loaded much later in the countdown—the v1.1 requires its propellants to be loaded much earlier. Approximately 3 hours and 50 minutes before T-0, the process of loading about 262,570 pounds (119,100 kg) of highly refined rocket-grade kerosene (known as “RP-1”) into the booster’s first-stage fuel tanks got underway, followed by some 609,800 pounds (276,600 kg) of liquid oxygen. “To enable safe tanking and operation of this fuel, the ground and rocket facilities need to be chilled-down along with all piping, valves and ancillary equipment,” noted AmericaSpace’s Launch Tracker, run by Mike Barrett, at 7:55 a.m. PST (10:55 a.m. EST). “This prevents the possibility of a component failing through thermal shock.” A combined total of 61,400 pounds (27,850 kg) of RP-1 and 142,900 pounds (64,820 kg) of liquid oxygen were also loaded aboard the second stage, supporting the single Merlin 1D Vacuum engine, which would execute a pair of “burns” to deliver Jason-3 into orbit. When all the propellants were aboard the vehicle, the liquid oxygen entered a “topping-off” mode, as boiled-off cryogens were continuously replenished until close to T-0.
The weather situation remained acceptable, despite the arrival of coastal fog, which rolled over SLC-4E and obscured the Falcon 9 by 8:30 a.m. PST (11:30 a.m. EST). “The fog is anticipated to disperse before the launch terminal countdown,” our Launch Tracker pointed out. Customary checks of the Flight Termination System (FTS)—which would activate on-board ordnance to destroy the booster, in the event of a major contingency during ascent—were performed and shortly before 9:50 a.m. PST (12:50 p.m. EST) the L-1 Hour Weather Briefing confirmed a zero-percent likelihood of any Launch Commit Criteria (LCC) being broken. “There will be some fog around which is denser than was forecast,” explained the Tracker, “but it will not affect the launch.” High-altitude weather balloon data confirmed that upper-level winds were “Green” (“Go”), well within acceptable limits.
At T-13 minutes, the Launch Director ran through a poll of all 19 stations, each of which crisply reported their readiness to support the launch, despite a slight delay from the Ground Control and Software Control consoles. Passage through this polling phase allowed the Launch Director to issue permission to the Launch Conductor to press into the Terminal Countdown at T-10 minutes. During these final minutes, the final v1.1 transitioned to internal power and assumed primary control of its on-board critical functions, as well as chilling-down the Merlin 1D first-stage engines to properly condition them, ahead of the onset of their ignition sequence at T-3 seconds.
Despite a minor issue with the Merlin 1D Vacuum second-stage engine, at 10:36 a.m. PST (1:36 p.m. EST), the approximately 90-second retraction of the strongback from the vehicle got underway. As the clock continued ticking, the FTS was activated, liquid oxygen replenishment was terminated, all propellant tanks were pressurized and the Launch Director issued a final “Go for Launch” at T-2 minutes. At the same time, the Air Force Range Safety Officer (RSO) also confirmed the range’s preparedness to support the launch. The nine Merlin 1D first-stage engines were purged with inert gaseous nitrogen, the Range Operations Co-ordinator (ROC) confirmed “Range Green” at T-40 seconds and the v1.1’s propellant tanks were verified at flight pressures at T-30 seconds.
With SLC-4E’s “Niagara” deluge system by now in full flow, depositing 30,000 gallons (113,500 liters) of water, per minute, across the pad surface and flame trench, the nine Merlins ignited at T-3 seconds, quickly ramping up to a combined 1.3 million pounds (590,000 kg) of thrust, and the vehicle departed Vandenberg precisely on the opening of the window at 10:42:18 a.m. PST (1:42:18 p.m. EST).
Rising rapidly into the murky California sky, the Falcon 9 passed Mach 1 within 70 seconds and proceeded through a period of maximum aerodynamic pressure—known colloquially as “Max Q”—where atmospheric effects upon its airframe reached their most severe. At 10:44 a.m. PST (1:44 p.m. EST), about 2.5 minutes into the uphill climb, the engines shut down and the first stage was jettisoned a few seconds thereafter. This established the proper conditions for the ignition of the Merlin 1D Vacuum engine on the second stage, which was destined to conduct two burns to inject Jason-3 into orbit. The first of these burns ran for a little over six minutes, producing 180,000 pounds (81,600 kg) of thrust, during which period the PLF was discarded, exposing Jason-3 to the space environment for the first time. The Merlin 1D Vacuum engine shut down at 10:51:18 a.m. PST (1:51:18 p.m. EST), about nine minutes after departing Vandenberg, after which a 46-minute “coast” ensued, prior to a relighting of the second stage to establish the satellite into its desired orbit.
In the meantime, the “West Coast” Autonomous Spaceport Drone Ship (ASDS)—nicknamed “Just Read the Instructions”—had been positioned about 173 miles (278 km) to the south of Vandenberg, off San Diego. Although Just Read the Instructions has been used for previous East Coast oceanic landing attempts, another drone ship, “Of Course I Still Love You”, will be dedicated to future SpaceX landing operations from Cape Canaveral Air Force Station, Fla. AmericaSpace has been advised by SpaceX that all Falcon 9 first-stage hardware for the “next few missions” will attempt oceanic landings on the ASDS. “For Jason-3, we didn’t receive environmental approval for a land landing in time for the launch, so we are doing it on the drone ship,” we were advised, “plus this is good practice for future high-velocity launches that don’t enough of a delta-velocity budget to return to the launch site.”
Today’s landing was hoped to mark the first wholly successful touchdown of Falcon 9 first-stage hardware on the ASDS. Two previous attempts were made in January and April 2015, during the opening minutes of the CRS-5 and CRS-6 Dragon ascents. In the first instance, the booster reached the deck—a remarkable technical achievement in its own right—but suffered a premature exhaustion of hydraulic fluid in its hypersonic grid fins, causing it to impact at a 45-degree angle and explode, whilst on the second occasion the stage experienced excessive lateral movement in its final seconds of descent, causing it to topple after alighting on the ASDS. A spectacularly successful touchdown on solid ground, at Landing Zone (LZ)-1 at Cape Canaveral Air Force Station, was accomplished using the Upgraded Falcon 9 first stage on 21 December. It is understood from SpaceX, however, that ASDS landings must be perfected in order to cater “for future high-velocity launches that don’t have enough of a delta-velocity budget to return to the launch site.”
Efforts to guide the first-stage hardware down to the ASDS got underway immediately after it separated from the remainder of the Falcon 9, by which time it was traveling at a velocity of 2,900 mph (4,670 km/h). Maintaining stabilization during these excessive aerodynamic conditions has been likened to balancing a rubber broomstick in the palm of the hand, whilst in the midst of a fierce windstorm. An initial “boost-back” burn got underway at 10:46 a.m. PST (1:46 p.m. EST), effectively flipping the 150-foot-tall (46-meter) first stage over, to protect the engines in the run-up to atmospheric re-entry. A second firing, known as the “retro-propulsion” or “re-entry” burn, began at 10:49 a.m. PST (1:49 p.m. EST) and served to slow the incoming first stage to about 560 mph (900 km/h). During this time, the four hypersonic grid fins, configured in an “X-wing” layout and tasked with controlling the lift vector, were successfully deployed.
Finally—and most critically—the “landing” burn was due to occur at 10:53 a.m. PST (1:53 p.m. EST), with great anticipation that the first stage would alight on the ASDS in a similarly smooth fashion to that seen a few weeks ago at LZ-1. It was expected that this third and final burn would slow the vehicle to just 4.5 mph (7.2 km/h). Maddeningly, however, the video feed from the ASDS was lost in these final crucial moments, due to a combination of factors, including its oceanic position and the presence of heavy waves.
Of course, the insertion of Jason-3 into orbit remained the primary objective of the mission, but the return of the first stage to the deck of the ASDS naturally attracted much attention. At 11:11 a.m. PST (2:11 p.m. EST), about 29 minutes after launch, the bittersweet news emerged from SpaceX: the first stage had reached the deck and had landed on-target, but had done somewhat harder than expected, resulting in the breakage of one of its four landing legs. “Reporter said the booster was not upright on the barge,” AmericaSpace’s Launch Tracker noted, “but they were exactly where they expected to be.”
The booster’s legs span about 60 feet (18 meters) when fully unfurled, which provide sufficient stability, although it remained to be seen how a broken member would affect its status. “First stage on target at drone ship, but looks like hard landing; broken landing leg,” SpaceX tweeted, but added: “Primary mission remains nominal.” It subsequently became apparent that the failure of one of the legs to latch had caused the stage to topple over, as evidenced by an image issued by SpaceX CEO Elon Musk, who later tweeted: “Touchdown speed was ok, but a leg lockout didn’t latch, so it tipped over after landing.”
Meanwhile, after a successful 46-minute coast, the Merlin 1D Vacuum engine ignited for the second occasion at 11:37 a.m. PST (2:37 p.m. EST) and burned for about 30 seconds, prior to the separation of Jason-3 into an orbit whose perigee will draw it as close as 825 miles (1,328 km) to Earth and as far as 857 miles (1,380 km) at apogee. The spacecraft’s twin solar arrays were deployed shortly afterwards and were fully unfurled by 11:48 a.m. PST (2:48 p.m. EST). It is anticipated that Jason-3 will remain operational for at least three years.
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